The orally administered solid unit dosage forms heretofore recognized in the pharmaceutical industry are generally divisible into two basic forms, i.e. tablets and capsules. There are various broad categories of both tablets and capsules recognized in the art such as, for example, those which are enteric coated to release medication in the intestinal tract, those which, by various mechanisms, release medication over an extended period of time, effervescents and the like. By and large such conventional solid oral dosage forms suffer from a number of disadvantages.
First, conventional solid oral unit dosage forms are disadvantageous in that each contains, admixed with the active ingredient a plurality of various substances which are termed "therapeutically inert or non-toxic, pharmaceutical adjunct materials". Such materials fall under the art-recognized categories of diluents, excipents, binders, lubricants, disintegrants, stabilizers, buffers, preservatives and the like. Although these materials are recognized as indispensible in the art of pharmaceutical compounding, their use nonetheless presents problems which must be dealt with from a viewpoint of cost, final size and weight of the dosage unit and the like. Additionally, each such adjunct material must be evaluated before use in terms of potential incompatibilities with the medicaments present. Further, certain of these materials, e.g. lubricants, may present problems concerning the bioavailability of the active ingredient. Also, the presence of such materials must be considered in analytical procedures utilized to test for potency etc. of the finished dosage form.
A second primary disadvantage in solid oral unit dosage forms known to the art is that the methods available for assay thereof involve destruction of the dosage form thereby permitting the testing of only a small percentage of such forms actually produced. Therefore, it is recognized in the art that there can be considerable deviation within a given batch of such dosage forms since the mean of dosage, performance, etc. for each batch deviation is determined by analysis of a relatively minor number of samples.
The batch concept in itself is a disadvantage to prior art oral solid dosage forms simply from the viewpoint of the economics of the batch designation, control and evaluation.
In accordance with the present invention, solid dosage units primarily for oral ingestion are provided which are producible in large numbers at high speed and, because they are prepared by a method unique in the pharmaceutical industry, they do not suffer from the above enumerated disadvantages of currently available solid oral dosage forms, i.e. tablets and capsules. This method is highly advantageous in that it eliminates the necessity for batch requirements as they are conventionally recognized; provides for continuous on-line analysis for potency as well as on-line performance evaluation of the dosage forms as they are being produced; provides the substantial elimination of the necessity of mixing conventional pharmaceutical adjunct materials with the medicaments with the exception of glidants which may be required to facilitate the flow of powders and/or certain other materials advantageous for product performance; and provides pharmaceutically elegant unit dosage forms which can be engineered to release medicament at any desired rate and which are capable of a rate of release faster than commercial tablets and capsules presently available. In summary, the dosage forms of the invention provide assurance that a larger percent of a more accurately measured amount of medication will be available in a more precisely controlled time after ingestion than is the case with present commercial units.
The oral unit dosage forms of the present invention are advantageous in a number of important respects, foremost of which is the fact that they are substantially qualified by on-line procedures during high-speed, substantially automated manufacturing operations. In addition, the dosage forms of the present invention are also advantageous in that the medicament contained therein is released for absorption with exceptional uniformity over a large number of dosage units. Further, the dosage units of the invention can be engineered to release medication within a shorter period of time after ingestion than is possible with solid oral dosage forms, e.g., tablets and capsules, presently available. Therefore, the dosage units of the invention provide superior consistency both in content of medicament and release thereof for absorption.
Regarding the prior art, the following publications, which are directed to solid dosage forms distinguishable from conventional tablets are noteworthy. Russell, U.S. Pat. No. 3,444,858 issued May 20, 1969 describes a vehicle for the buccal administration of medicaments comprising a strip of gelatinous material containing medication, said strip being divided into sections each of which is connected to the next by easily tearable ligaments. In use, a section is merely separated from the strip and placed in the mouth.
A second publication warranting mention is an article in the New England Journal of Medicine, Vol. 289, No. 10 pp. 533-5 (1973). This article describes a means whereby birth control medication is being made available to women in the Peoples Republic of China on a very large scale. In this method, a sheet of colored, water-soluble, carboxymethylcellulose paper is treated with a solution of progestational and estrogenic materials. The sheet is then perforated and cut into strips. The medicament is packaged as a strip of 22 "squares" which are torn from the strip and taken daily. This method does not provide for the concealment of the drug in the final dosage form, thereby suffering from the disadvantage of potential contamination and/or inactivation of the medication once the package is opened. Further, by virtue of not being completely unitized, such perforated strips can give rise to uneven tearing at the perforations and potentially, disproportionant dosage.
Finally to be considered is Higuchi et al. U.S. Pat. No. 3,625,214 issued Dec. 7, 1971 which describes a dosage form utilized for controlled, i.e. sustained release of medicaments. The dosage form is comprised, in essence, of a medicament containing martix which is coated on a substrate which is then spiral wound to a final "jelly roll" appearance. After ingestion, the medicament is released by the gradual erosion of the outer layers of substrate and also by diffusion from the sides where there is exposed medicament. There is no disclosure of whether the disclosed dosage forms are amenable to high capacity pharmaceutical manufacturing. There is further no disclosure of means whereby the disclosed dosage forms can be rendered into pharmaceuticlly elegant finished products.
In distinct contrast to the teachings of the foregoing publications, the novel solid dosage units of the present invention are completely unitized, amenable to non destructive, on-line analytical testing during high capacity pharmaceutical manufacturing operations, are essentially free from pharmaceutical adjunct materials that may interfere with performance, have no exposed medicament and have a superior consistency of release of medicament which enhances the efficacy thereof.